What is the best way to book in France, pay the french price and pick up the ticket in France.
You don't need to book in France, just go to your favorite *A carrier in Canada (or your favorite travel agency

) and book a ticket originating in France. The RTW price ex France will apply and it will be coverted to CAD at the respective rate of exchange. The ticket can be issued TOD (ticket on departure) AFAIK.